Maybe in the future building materials are amazing...
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MichaelJan 16 '12 at 20:30

8

Nuclear weapons don't have to create larger explosions than can be created by a conventional explosive weapon. Have you never heard of a tactical nuclear weapon?
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agent86Jan 16 '12 at 20:39

@agent86: Even the smallest tactical nuclear weapons have bigger explosions than those in starcraft. In this case, however, comes another question: why don't the Terrans use big, strategical nuclear weapons? I'm just looking for a possible in-universe explanation, I did not ask this question to criticize the game!
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vszJan 16 '12 at 20:42

1

I've made an edit based on the answer & comments here. Hopefully it keeps the essence intact while reducing some of the concerns...
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Matthew ReadJan 19 '12 at 17:14

7

Because game design decisions should not be made with too much of a regard for reality.
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DecencyFeb 1 '12 at 13:21

The colonists of Korhal IV rebelled against their former masters, the Terran Confederacy. The latter resorted to assassinating its first leader with ghosts but still failed to control the rebellion. The Confederacy resorted to firing a thousand Apocalypse-class nuclear missiles at Korhal from the distant Confederate capital of Tarsonis, killing four million people and destroying most life on the planet and setting the forests on fire.

After the Korhal incident, full-scale use of nuclear weapons were banned on habitable worlds. The Confederacy began using smaller missiles, targeted by ghosts

RavenDreamer also found this from the SC1 manual:

Although our typical image of a nuclear weapon is something that obliterates a large area, tactical nuclear devices exist today, and were deployed as far back as the 1960s during the cold war. Although nuclear weapons generally produce a much larger and more devastating/deadly explosion than conventional bombs, there are conventional bombs with more explosive force than the smallest nuclear weapons.

Theoretically, a bomb launched from a silo and laser guided to a ground target could do damage consistent with the StarCraft nuke, although I do not believe this has ever happened in a war scenario.

which makes no sense in the context of defending against a huge Zerg onslaught :D
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AsdafghJan 16 '12 at 21:36

2

For what it's worth, the original Starcraft manual (which the wiki alludes to, but does not quote) mentions using so-called "mini-nukes" with ghosts, rather than the big bombs.
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Raven Dreamer♦Jan 16 '12 at 21:41

2

@vsz: It seems likely that once they were banned, The Confederacy would dispose of all the ones that they could find.
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UllallullooJan 19 '12 at 16:53

2

Part of the problem is that this law was created in a time before the confederacy of man, pre-SC 1. Since the events of SC most of the governments in power have been working harder to weponize the Zerg then outright destroy them. I would also suggest that given Zergs ability to burrow into the earth, and survive in deep space, not to mention other extremophile characteristics, a nuclear device would not actually guarantee the destruction of the Zerg. The Protoss weapons they use to cleanse a planet is clearly more destructive then a normal nuclear strike.
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PyrodanteJan 19 '12 at 21:13

2

Also: Mengsk is barely holding on to the Confederacy as it is, if he revered the very decision that led to the foundation of his power block (Sons of Korhal), it would be a very bad move politically.
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PyrodanteJan 19 '12 at 21:15

Well, the units in SCII, in-universe, would actually equate to whole platoons/armies of that unit..... when one takes that into account, the nuke size is very large indeed, or would be in-universe comparatively.